Mineral oil is made from petroleum. Do NOT use it on a pan you intend to use for cooking food!
Please do not do this, cast iron can crack and also warp from this treatment (as well as with throwing in the fire). Cast iron is wonderful for retaining heat, but it has never been meant to withstand a temp of 500 and in some of the more modern ovens 1200. There are many wonderful resources out there for care of cast iron, spend a half hour and research the one best for you.
My best friend cleans her cast iron cookware and ALL of her oven safe cookware, bakeware, utensils and even the burner grates this way. She swears by it and has done this for several years.
Thank you for opening up the floor to discuss the best method for cleaning cast iron. Recently, I've done the clean it with a paper towel, pour in salt and rub with a fresh paper towel, heat to remove excess food and oil it lightly method. It does work well. My cast iron has to be cared for as one piece belonged to my great-grandmother!
Deep is so correct, you should NEVER EVER use dish soap to clean your cast iron skillet.
You can avoid having to do this by never, EVER washing cast iron in soap. Soap is what ruins the seasoning of the pan. Wash it in hot water and use a spatula or firm plastic vegetable brush to get off any stuff. Then, put it on the stovetop, warm it up to completely dry it (this prevents rust), and spray a little olive oil on the warm pan. I've had my trusty big fryer for years and it still looks brand new and is totally non-stick.
This works great! I've been using this method since I learned it from my mother who made the best friend chicken on the planet. Thanks, KissaMew!
I tried to respond to this last night, but my system crashed in the middle of typing. I, like a previous poster do not recommend this method of "cleaning". First, NEVER "season" cast iron with vegetable products. It will create an almost "waxy" build-up" on your cookware that can only be removed with metal scrubbing pads...not a good idea! If you go the mineral oil route, why not just use motor oil?...basically the same end product. In my opinion, the ONLY proper "seasoning/prep" you should use is PORK FAT....that's right!...PORK FAT! My 3 cast iron skillets and one dutch oven will certainly never see the likes of what this poster proposes....and, every piece is old, yet all have cooking surfaces that are slick as glass, and are permaently "non-stick". If you can't deal with meat fat, perhaps some other cookware would be a better choice for you. If anything, the "oven cleaning cycle" is the very thing that WILL eventually cause cracks and wear on cast iron. It'll last several lifetimes if properly cared for. All of mine get the pork fat with high heat(not oven cleaning cycle) treatment about once a month, and daily on the ones that I use daily. I can cook an egg without additional oil/grease...totally non-stick. Take time to read up on the care of those precious hand-me-downs!
That is what she is doing, seasoning it....That is what i do, and it only makes it nonstick better...
For those that are unaware, super-heating cast iron in a manner such as this will destroy the seasoning in the pan (the dark layers that create the non-stick qualities).